Element Ratios Research Articles

Modelling chemical clocks. Theoretical evidences of the space and time evolution of [s/α] in the Galactic disc with Gaia-ESO survey

Chemical clocks based on s-process element/α element ratios are widely used to estimate the ages of Galactic stellar populations. However, the s/α versus age relations are not universal, varying with metallicity, location in the Galactic disc, and specific s-process elements. Moreover, current Galactic chemical evolution models struggle to reproduce the observed s/α increase at young ages, particularly for Ba. Our aim is to provide chemical evolution models for different regions of the Milky Way (MW) disc in order to identify the conditions required to reproduce the observed s/H s/Fe and s/α versus age relations. We adopted a detailed multi-zone chemical evolution model for the MW including state-of-the-art nucleosynthesis prescriptions for neutron-capture elements. The s-process elements were synthesised in asymptotic giant branch (AGB) stars and rotating massive stars, while r-process elements originate from neutron star mergers and magneto-rotational supernovae. Starting from a baseline model that successfully reproduces a wide range of neutron-capture element abundance patterns, we explored variations in gas infall/star formation history scenarios, AGB yield dependencies on progenitor stars, and rotational velocity distributions for massive stars. We compared the results of our model with the open clusters dataset from the sixth data release of the Gaia -ESO survey. A three-infall scenario for disc formation aligns better with the observed trends. The models capture the rise of s/α with age in the outer regions but fail towards the inner regions, with larger discrepancies for second s-process peak elements. Specifically, Ba production in the last 3 Gyr of chemical evolution would need to increase by slightly more than half to match the observations. The s-process contribution from low-mass ( 1.1 M_⊙) AGB stars helps reconcile predictions with data but it requires a too-strong increase that is not predicted by current nucleosynthesis calculations, even with a potential i-process contribution. Variations in the metallicity dependence of AGB yields either worsen the agreement or show inconsistent effects across elements, while distributions of massive star rotational velocities with lower velocity at high metallicities fail to improve results due to balanced effects on different elements. The predictions of our model confirm, as expected, that there is no single relationship s/α versus age and that it varies along the MW disc. However, the current prescriptions for neutron-capture element yields are not able to fully capture the complexity of evolution, particularly in the inner disc.

Treasure Bowl: PM2.5 Aggregation in the Eye of a Tropical Cyclone

AbstractA local tropical cyclone (TC) in South China Sea was observed making its first complete landfall on an island. Following the arrival of the TC eye, PM2.5 concentration rose from 4 µg/m³ to 44 µg/m³. Mass reconstruction results reveal that sea salt emerged as the primary source. The similar molar ratios of elements before and after landfall confirm that the source of PM2.5 is associated with the local terrigenous sediment. The ratio of Na+/Cl− in the TC eyewall is approximately 5:1 indicating the existence of chlorine depletion. Meanwhile, the concentration of Cl− and molar ratios like Si/Fe inside the TC eyewall show a rapid increase, and reach a peak in the TC eye, indicating that marine particulate matter invades and presents a treasure‐bowl‐like stepwise aggregation. Our findings provide statistical and theoretical foundations for understanding extreme air pollution events, offering direct evidence of sea‐land transport throughout the entire TC.

Volcanic aerosols captured by plants: A study of nanoparticles and their chemical composition.

Nanoparticles (NPs) exhibit high reactivity and mobility in the environment, and a significant capacity to penetrate living organisms, potentially leading to harmful effects. Volcanoes are the second major source of natural NPs emitted into the atmosphere, with an estimated flux of 342 Tg/year. Few studies have focused on their fate. Thanks to technological advances in single-particle inductively coupled plasma mass spectrometry (spICP-MS), this trend is starting to reverse. La Soufrière volcano in Guadeloupe, chosen as a case study, exhibits increasing hydrothermal activity since its last eruption in 1530. This study aims to characterize NPs produced during volcanic activity by analysing ancient ash deposits, as well as those formed during periods of volcanic inactivity by examining condensates near fumaroles, as ultrafine particles are primarily generated through gas condensation. In this study, plants are utilized as samplers for NPs produced by fumarole activity. The use of a ICP-MS time-of-flight in single particle mode (spICP-ToF-MS), combined with data processing techniques such as hierarchical agglomerative clustering, enables the detailed characterization of NPs by determining their multi-element composition, concentration, and mass distribution. The results demonstrate that plants can effectively serve as samplers, even under the extreme environmental conditions present at the volcano's summit. However, differences in their efficiency at trapping particles on leaf surfaces can be attributed to varying physical characteristics of the plants. The spICP-ToF-MS analysis identified three types of multi-elemental NPs (NP-Al+Si, NP-Al+Fe, NP-Ti+Al) and three mono-elemental NPs (NP-Al, NP-Si, NP-Fe). Additionally, NPs containing trace elements were detected exclusively in undiluted Sphagnum pore water, where one tri-elemental NP (Sr-Ce-La), one bi-elemental NP (CeLa), and nine mono-elemental NP families (Cr, Cu, Zn, Sr, Y, Zr, Ba, La, Ce) were identified. Elements with potential negative effects on biota such as Cu, Zn, and Cr were also highlighted. Furthermore, the composition of the total of NPs (excluding families) is compared with elemental ratios from materials of different origins (volcanic, detrital, atmospheric) to validate their volcanic source.

Multiscale study on the compressive performance of diverse solid waste backfill bodies

To create green, low-energy self-compacting backfill materials, this study utilizes aeolian sand, slag, red mud, and calcium carbide slag to prepare diverse solid waste backfill materials in synergy. Additionally, a suitable amount of polypropylene fibers is added to enhance its toughness. During the experimental process, unconfined compressive strength tests were conducted using digital speckle technique. Computerized tomography scanning technology was employed for internal 3D visualization of the samples. Material strength difference mechanisms were characterized using SEM–EDS and XRD microscopic techniques. Finally, discrete element numerical simulation was utilized for analyzing the evolution of sample failure. The results show that with the increase in calcium carbide slag doping, the specimen UCS increases and then decreases, and when the doping of calcium carbide slag is 14%, the specimen UCS reaches a local maximum of 3.552 MPa; with the increase in the water–solid ratio, the specimen UCS gradually decreases, and when the water–solid ratio is 0.3, the specimen UCS reaches a local minimum of 3.26 MPa. With the increase in calcium slag doping, the mass percentage of calcium element and calcium-silicon ratio in the multi-solid waste matrix first increased and then decreased, and the micro-morphology of the multi-solid waste matrix included lamellar, block, and rod structures; With the increase in the water–solid ratio, the micro-morphology of the multi-solid waste matrix was gradually transformed, and the pore defects between the cementitious materials gradually increased. With the increase in calcium carbide slag doping, the porosity within the unit decreases, and when the doping of calcium carbide slag exceeds 14%, the porosity increases and the compressive strength decreases; with the gradual increase in the water–solid ratio, the porosity within the unit gradually increases, and the number of holes in the specimen reaches a minimum of 208 within the range of the study when the water–solid ratio is 0.24. Digital speckle technique and PFC numerical simulation together elucidate the sample’s failure process and crack evolution mechanism. Initially, the internal voids of the sample are gradually compacted, and crack propagation is slow. As the load increases to the peak, localized deformation and macroscopic crack formation occur in the sample. After the peak load, the sample exhibits significant displacement deformation, and the number of cracks increases significantly. The research findings can provide reference for the design and construction of solid waste backfill pipelines and trenches.

Phase stability, electronic, mechanical, lattice distortion, and thermal properties of complex refractory-based high entropy alloys TiVCrZrNbMoHfTaW with varying elemental ratios.

This study examines the intricate area of refractory-based high entropy alloys (RHEAs), focusing on a series of complex compositions involving nine diverse refractory elements: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W. We investigate the phase stability, bonding interactions, electronic structures, lattice distortions, mechanical, and thermal properties of six RHEAs with varying elemental ratios using VASP and OLCAO DFT calculations. Through comprehensive analysis, we investigate the impact of elemental variations on the electronic structure, interacting bond dynamics, lattice distortion, thermodynamic, mechanical, and thermal properties within these RHEAs, providing an insight into how these specific elemental variations in composition give rise to changes in the calculated properties in ways that would guide future experimental and computational efforts. The correlation between the lattice distortion, mechanical, and thermal properties is explored in detail in this work. Our findings reveal significant insights into how these factors contribute to the unique properties of RHEAs, such as enhanced strength, ductility, and resistance to corrosion and wear. This research not only advances our understanding of the fundamental aspects of RHEAs but also opens new avenues for the design and application of these materials in various industrial sectors.

A Novel (AlCrNbTaTi)N Multilayer Hard High-Entropy Alloy Nitride Coating with Variable Aluminum Content Deposited by Cathodic Arc Ion Plating

Traditional binary coatings like TiN and CrN display limited thermal stability and wear resistance under extreme conditions. High-entropy alloy nitride (HEAN) coatings offer a promising solution due to their customizable composition and unique properties, including high hardness, corrosion resistance, and thermal stability. This study focused on (AlCrNbTaTi)N HEAN coatings to address a critical need for materials capable of enduring extreme mechanical and tribological demands by examining the impact of aluminum content on their structural and mechanical properties, providing insights for optimizing coatings in harsh conditions through a self-assembled nanolayer structure with enhanced resilience and performance. The coatings were deposited via a cathodic arc by employing an AlCrNbTaTi alloy target composed of aluminum (20, 50, 60, 70%) and equal molar ratios of Cr, Nb, Ta, and Ti. The coatings were characterized through grazing incidence X-ray diffraction, SEM, HR-TEM, a nano-indentation test, and a friction and wear test. The results indicated that with increasing Al content, the structure of (AlCrNbTaTi)N coatings shifted from FCC to an amorphous state, leading to a reduction in the hardness and elastic modulus, accompanied by an increase in the wear rate and friction coefficient. The (AlCrNbTaTi)N coating, with an equal atomic ratio of metallic elements, showed potential as a hard tool coating. It demonstrated outstanding mechanical and tribological properties, with a 34.5 GPa hardness, 369 GPa modulus, 0.35 friction coefficient, and 8.2 × 10−19 m2·N−1 wear rate. The findings highlight the potential of (AlCrNbTaTi)N coatings to extend tool life and improve operational efficiency, helping advance materials engineering for industrial applications.

Study on Design, Synthesis and Performance Control of New Electrode Materials for High Energy Density Lithium Ion Batteries

In view of the limitations of traditional electrode materials for lithium-ion batteries, such as LiCoO2, LiMn2O4 and LiFePO4, Li[NiₓMn₁-x-yCoₙ]O₂, a lithium-rich manganese-based ternary composite, was explored in this paper, and carbon nanotubes (CNTs) were introduced for surface modification to improve the electrochemical performance of the materials. The composite was synthesized by coprecipitation method and calcined at 800-900℃ for 4-6 hours to form the final material. Performance control includes surface modification, doping modification and coating treatment to optimize conductivity, structural stability and cycle stability. The analysis through X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicates that the synthesized material exhibits a well-defined crystalline structure and favorable micro-morphological characteristics. Electrochemical evaluations demonstrate that this material possesses a significant specific capacity, alongside robust cycling stability and superior rate capability. Discussions on the underlying mechanisms highlight how adjusting elemental ratios, incorporating dopants, and applying surface modifications can enhance material performance. This research successfully fabricated lithium-rich manganese-based ternary composite materials with outstanding electrochemical attributes, thereby offering both theoretical insights and technical foundations for advancing high energy density lithium-ion batteries.

Otolith chemistry suggests population heterogeneity within a genetically homogeneous Indian scad population along Indian coast

The Indian scad, Decapterus russelli is one of the most exploited pelagic resources of India. Population genetic analyses using mitochondrial and nuclear markers indicated a lack of genetic structuring among populations from Indian waters. As this species is highly migratory, it is also important to establish the environmental influence on its population structure. In the present study, the whole sagittal otolith composition was analysed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to assess spatial distribution of D. russelli collected from 4 sites along the Indian coast. Elemental ratios (Ba/Ca, Fe/Ca, K/Ca, Mg/Ca, Na/Ca, Sr/Ca and Zn/Ca) were analysed using univariate and multivariate statistics to determine whether this chemical signature can provide insight into the adaptive patterns. All element/Ca ratios are found to be significantly different between the four sampling locations (ANOVA, p < 0.05; MANOVA, p < 0.05). Five of the element/Ca ratios were found to be significantly different when the data was analysed coastwise (ANOVA, p < 0.05; MANOVA, p < 0.05). The LDA plot also showed the spatial heterogeneity of Element/Ca ratios between the four sampling sites, but some overlaps were also observed, reflecting the migratory ability of the species. This basic information on spatial ecology is required for formulating effective management and conservation strategies for the species.

Contamination assessment and source identification of metals and metalloids in submicron road dust (PM1) in Moscow Megacity.

The content of 39 metals and metalloids (MMs) in submicron road dust (PM1 fraction) was studied in the traffic zone, residential courtyards with parking lots, and on pedestrian roads in parks in Moscow. The geochemical profiles of PM1 vary slightly between different types of roads and courtyards but differ significantly from those in parks. In Moscow, compared to other cities worldwide, submicron road dust contains less As, Sb, Mo, Cr, Cd, Sn, Tl, Ca, Rb, La, Y, U, but more Cu, Zn, Co, Fe, Mn, Ti, Zr, Al, V. Relative to the upper continental crust, PM1 is highly enriched in Sb, Zn, Cd, Cu, W, Sn, Bi, Mo, Pb. In the courtyards, where contact between pollutants and the population is most frequent and occurs over an extended period, the level of PM1 pollution with MMs (from strong to extreme) is comparable to that on large roads. Source identification was conducted using correlations, elemental ratios, and absolute principal component analysis with multiple linear regression (APCA-MLR). In the traffic zone, non-exhaust and exhaust vehicle emissions contribute significantly to the MM concentrations in PM1 (especially for Bi, Sb, Sn, V, Fe, Cu, W, Mo); soil particles, abrasion of steel surfaces, industrial emissions, tire and road wear with carbonate dust resuspension contribute less. In the courtyards, the contribution of the road wear with carbonate dust resuspension and soil particles increases by up to 16% due to the poor condition of the road surface, frequent construction works, and large contact areas of roads with soils. In parks, the contribution of anthropogenic sources sharply decreases by 20-48% due to the increased soil resuspension rate. The spatial distribution pattern of MMs in submicron road dust should aid in the development of more effective road surface washing strategies, ultimately minimizing the risk to public health.

Cu2O1-x-Superlattices Induced Oxygen Vacancy for Localized Surface Plasmon Resonance.

Metallic oxide can induce localized surface plasmon resonance (LSPR) through creating vacancies, which effectively achieve high carrier concentrations and offer advantages such as versatility and tunability. However, vacancies are typically created by altering the stoichiometric ratio of elements through doping, and it is challenging to achieve LSPR enhancement in the visible spectral range. Here, we have assembled Cu2O1-x-superlattices to induce a high concentration of oxygen vacancies, resulting in LSPR within the visible spectrum. Combining this technique with theoretical models, we have elucidated the mechanism behind the origin of LSPR. We also provide evidence of strong and uniform LSPR exhibited by this structure under visible light. This significantly enhances the electromagnetic field in semiconductor-based surface-enhanced Raman scattering (SERS), with a detection limit concentration reaching 10-9 M compared to conventional gold nanoparticles (55 nm). Our strategy provides a new perspective and potential for controlling carrier concentration and generating LSPR in metal oxide nanoparticles.

Unraveling the role of E. coli and calf intestinal alkaline phosphatase in calcium phosphate synthesis.

The enzyme-catalyzed synthesis of calcium phosphate is a promising method for producing calcium-based nanomaterials for biomedical applications. The purpose of this work was to determine the type of phosphate that forms when alkaline phosphatase catalyzes the reaction, and to identify the role of natural biopolymers in calcium phosphate formation. In this research, we analyzed calcium phosphates that were synthesized in the presence of alkaline phosphatase from either E. coli or calf intestinal, analyzed the obtained nanoparticles and compared them by functional composition, elemental ratio, and morphology. Since all syntheses were performed in Tris buffer with the addition of MgCl2, the final depleted hydroxyapatite incorporated magnesium. It was found that in the first 24 h, the reaction product form is determined by the enzyme source as well as the presence of other biopolymers (in particular, humic acid) in the reaction mixture. Hollow nanospheres of the depleted hydroxyapatite were obtained as a final product for both E. coli and calf-intestinal alkaline phosphatase during a 7-day reaction. When humic acid was added into the reaction mixture, separate spheres of the depleted hydroxyapatite were observed during a 24-h reaction. When Mg ions are present in the reaction mixture as a buffer component, they are evenly incorporated into the structure of the resulting calcium phosphate. The data obtained can be useful in understanding the calcification process of bioobjects and in applying the enzymatic method of calcium phosphate synthesis to biomedical applications.

Preparation of CMC/ACP/PHMB nanocomposites and preliminary study on their antibacterial and remineralization functions.

Caries is a chronic oral disease causing a series of complications. This study aims to develop a material that could remineralize demineralized enamel and simultaneously exert antibacterial effects. A carboxymethyl chitosan (CMC)/amorphous calcium phosphate (ACP)/polyhexamethylene biguanide hydrochloride (PHMB) nanocomposite was synthesized for the first time, and its stability, remineralization ability, and antibacterial properties were investigated in this study. PHMB has excellent antibacterial properties, was used as an additive to stabilize ACP. The enamel surface covered with CMC/ACP/PHMB showed a uniform layer with a similar elemental ratio to that of natural hydroxyapatite and the ratio of crystal diffraction peaks was close to that of natural enamel. The mechanical properties, including hardness and elastic modulus, of the enamel in all experimental groups were restored. The antibacterial effect of 240 mg/L CMC/ACP/PHMB was comparable to that of 0.12% CMC/ACP/chlorhexidine. This study provides a theoretical and experimental basis for the development of novel dual-function anticaries agent.

Metal-bound carbon and nutrients across hydrologically diverse boreal peatlands

Boreal peatlands store abundant carbon (C) belowground because of saturated conditions and cold temperatures, which inhibit the enzymatic release of dissolved organic carbon (DOC) from organic matter. However, metals may also bind DOC, as well as nitrogen (N) and phosphorus (P), and their impact may vary among peatlands with differing hydrology. To assess variation of metal-C-nutrient interactions within and among peatlands and with depth, we sampled cores from seven peatlands in the Marcell Experimental Forest, Minnesota, including bogs, poor fens, and a rich fen. We extracted peat with sodium sulfate to release elements bound with exchangeable metals such as calcium (Ca) or aluminum (Al), and with sodium dithionite to release elements bound with the redox-active metals iron (Fe) and manganese (Mn). We compared extracted elements to long-term peat porewater measurements. Mean DOC extracted by sulfate or dithionite in the bogs and poor fens was 5 or 8 times greater, respectively, than porewater DOC, and in the rich fen it was 8 or 38 times greater. Similarly, N and P extracted by sulfate and dithionite were 10–24 times higher than porewater in the bogs and poor fens and 7–55 times higher in the rich fen. The ratio and absolute values of redox-sensitive and ion-exchangeable elements varied by element among peatland types and with peat depth and values were not always greater in fens than bogs. We conclude that both redox-active (Fe) and non-redox-active (Ca and Al) metals bind important pools of peatland C and nutrients regardless of peatland hydrologic type and despite the very low total mineral content of these boreal peats.

Numerical Study on the Shear Behavior of a Late-Model Cold-Formed Stainless Steel C-Shaped Beam.

The failure mode of thin-walled C-channel beams typically manifests as premature local buckling of the compression flange, leading to insufficient utilization of material strength in both the flange and the web. To address this issue, this study adopts the approach of increasing the number of bends to reinforce the flange and adding V-shaped stiffeners in the middle of the web to reduce the width-to-thickness ratio of the plate elements, thereby delaying local buckling and allowing for greater plastic deformation. However, the challenge lies in the irregular cross-sectional shape and complex buckling patterns. Therefore, this paper aims to explore a suitable cross-sectional form to expand the application of stainless steel members. Subsequently, three-point bending tests were conducted on the optimally designed stainless C-channel beam with folded flanges and mid-web stiffeners. The finite element simulation results were compared and analyzed with the experimental results to validate the model's effectiveness. After verifying the correctness of the finite element model, this study conducted numerical parameterization research to investigate the effects of the shear span ratio, complex edge stiffeners, web height-thickness ratio, and V-shaped stiffener size on the shear performance of stainless steel folded flange C-beams. The results show that changing the shear span ratio has a significant impact on the shear capacity and vertical deflection deformation of components; increasing the web height-thickness ratio can enhance the shear capacity of the component; elevating the V-shaped stiffener size can slightly improve the shear capacity of components; and for the stainless steel C-shaped beam with folded flanges and intermediate stiffening webs, adding edge stiffeners cannot remarkably promote the shear capacity of the component.

Design and Optimization of W-Mo-V High-Speed Steel Roll Material and Its Heat-Treatment-Process Parameters Based on Numerical Simulation

W-Mo-V high-speed steel (HSS) is a high-alloy high-carbon steel with a high content of carbon, tungsten, chromium, molybdenum, and vanadium components. This type of high-speed steel has excellent red hardness, wear resistance, and corrosion resistance. In this study, the alloying element ratios were adjusted based on commercial HSS powders. The resulting chemical composition (wt.%) is C 1.9%, W 5.5%, Mo 5.0%, V 5.5%, Cr 4.5%, Si 0.7%, Mn 0.55%, Nb 0.5%, B 0.2%, N 0.06%, and the rest is Fe. This design is distinguished by the inclusion of a high content of molybdenum, vanadium, and trace boron in high-speed steel. When compared to traditional tungsten-based high-speed steel rolls, the addition of these three types of elements effectively improves the wear resistance and red hardness of high-speed steel, thereby increasing the service life of high-speed steel mill-roll covers. JMatPro (version 7.0) simulation software was used to create the composition of W-Mo-V HSS. The phase composition diagrams at various temperatures were examined, as well as the contents of distinct phases within the organization at various temperatures. The influence of austenite content on the martensitic transformation temperature at different temperatures was estimated. The heat treatment parameters for W-Mo-V HSS were optimized. By studying the phase equilibrium of W-Mo-V high-speed steel at different temperatures and drawing CCT diagrams, the starting temperature for the transformation of pearlite to austenite (Ac1 = 796.91 °C) and the ending temperature for the complete dissolution of secondary carbides into austenite (Accm = 819.49 °C) during heating was determined. The changes in carbide content and grain size of W-Mo-V high-speed steel at different tempering temperatures were calculated using JMatPro software. Combined with analysis of Ac1 and Accm temperature points, it was found that the optimal annealing temperatures were 817–827 °C, quenching temperatures were 1150–1160 °C, and tempering temperatures were 550–610 °C. The scanning electron microscopy (SEM) examination of the samples obtained with the aforementioned heat treatment parameters revealed that the martensitic substrate and vanadium carbide grains were finely and evenly scattered, consistent with the simulation results. This suggests that the simulation is a useful reference for guiding actual production.

Prospects on Mixed Tutton Salt (K0.86Na0.14)2Ni(SO4)2(H2O)6 as a Thermochemical Heat Storage Material

In this paper, a novel mixed Tutton salt (K0.86Na0.14)2Ni(SO4)2(H2O)6 was successfully synthesized as a single crystal and evaluated as a thermochemical heat storage material. Its thermal and thermochemical properties were correlated with the structure, which was determined by powder X-ray diffraction using the Le Bail and Rietveld methods. The elemental ratio between the K+ and Na+ monovalent cations was established by energy-dispersive X-ray spectroscopy. Similar compounds such as Na2Ni(SO4)2(H2O)4 and K2Ni(SO4)2(H2O)6 were also synthesized and used for structural comparisons. The (K0.86Na0.14)2Ni(SO4)2(H2O)6 salt crystallizes in monoclinic symmetry with the P21/c-space group, typical of hexahydrate crystals from the Tutton salt family. The lattice parameters closely resemble those of K2Ni(SO4)2(H2O)6. A comprehensive analysis of the intermolecular contacts, based on Hirshfeld surfaces and 2D fingerprint mappings, revealed that the primary interactions are hydrogen bonds (H···O/O···H) and ion-dipole interactions (K/Na···O/O···Na/K). The unit cell exhibits minimal void space, accounting for only 0.2%, indicative of strong atomic packing. The intermolecular molecular and atomic packing are important factors influencing crystal lattice stabilization and thermal energy supplied to release crystallographic H2O. The thermal stability of mixed Tutton salt ranges from 300 K to 365 K. Under the dehydration of its six H2O molecules, the dehydration reaction enthalpy reaches 349.8 kJ/mol, yielding a thermochemical energy storage density of 1.79 GJ/m3. With an H2O desorption temperature ≤393 K and a high energy storage density ≥1.3 GJ/m3 (criteria established for applications at the domestic level), the (K0.86Na0.14)2Ni(SO4)2(H2O)6 shows potential as a thermochemical material for small-sized heat batteries.

Optical remote spectral acquisition of elemental stoichiometry

Optical remote sensing (RS) enables the study of the elemental composition of Earth’s surface over broad spatial extents by detecting reflected electromagnetic radiation. Covalent bonds of macromolecular structures often reflect electromagnetic radiation at specific wavelengths, and in some cases relate to bonds of specific elemental identity. In other cases, interfering optical properties greatly impact the ability of RS to measure elements directly, but advances in statistical methods and the theoretical understanding of optical properties expand the capacity to quantify diverse elements in many systems. When applied under the framework of ecological stoichiometry, spatially and temporally explicit measurements of elemental composition permit understanding of the drivers of ecological processes and variation over space and through time. However, the multitude of available technologies and techniques present a large barrier of entry into RS. In this paper we summarize the capabilities and limitations of RS to quantify elements in terrestrial and aquatic systems. We provide a practical guide for researchers interested in using RS to quantify elemental ratios and discuss RS as an emerging tool in ecological stoichiometry. Finally, we pose a set of emerging questions which integrating RS and ecological stoichiometry is uniquely poised to address.

From the s-Process to the i-Process: A New Perspective on the Chemical Enrichment of Extrinsic Stars

Separating stars enriched in the s- and r-processes of nucleosynthesis is usually achieved by analyzing the element ratios of s-process elements (like Ba or La) to r-process elements (like Eu). The situation becomes more complex when analyzing CEMP-rs stars, which are carbon-enriched metal-poor objects enriched in a mixture of s- and r-elements. These objects, possibly resulting from the i-process of nucleosynthesis, are notoriously difficult to classify based on elemental ratios. Recent theoretical studies have outlined, however, that the s-, i-, and r-processes produce distinct isotopic mixtures. Here, we propose to analyze a sample of stars known to be enriched in s, r, or r + s elements and to determine the odd-to-even isotopic ratio measured on atomic lines of barium, in order to validate or disprove their assignation.

Суверенность психологического пространства личности в учебных группах полузакрытого типа (на примере кадетов и курсантов)

The relevance of studying the sovereignty of the psychological space of the individual in a semi-closed study group is derived from its role as an indicator of the ratio of individual and group elements, as well as its regulatory function. Objective: the goal of the study is to identify the manifestation degree of the sovereignty indicators of the personal psychological space and their correlation with socio-psychological characteristics in semi-closed educational groups at different levels of education (cadets and military students). Hypothesis: cadets, being a younger age group, experience the learning process in a semi-closed group more intensely than military students, which leads to a decrease in the manifestation degree of the sovereignty indicators. Participants: 222 respondents living and studying in Moscow (n = 107 cadets, aged 15-17, M = 15.9, SD = 0.69, 75% males and n = 115 military university students, aged 17-21, M = 18.4, SD = 1.88, 87% males). Methods (tools): the questionnaire ‘Sovereignty of Psychological Space – 2010’ (S. K. Nartova-Bochaver) was used to evaluate sovereignty; to analyze socio-psychological characteristics, the following methods were employed: the technique ‘Value-Accessibility Ratio in Different Life Spheres’ (E. B. Fantalova), ‘Group Cohesion Index’ methodology (K. Sisor), A. F. Fiedler’s method for diagnosing the psychological atmosphere of the team. Results: the study shows that cadets experience a greater traumatization of the sovereignty of the personal psychological boundaries than military students. ‘Normal’ levels of psychological sovereignty were associated with value system, personal experiences, collective cohesion, and team atmosphere. Main conclusions: the sovereignty indicators of the personal psychological space in a semi-closed educational group are determined by the organizational and educational setting of the institutions of different educational stages (secondary and higher education); socio-psychological characteristics play a supportive role in preserving sovereignty in the context of a semi-closed group. Practical Significance: findings can assist psychologists working with cadets and military university students in facilitating student adaptation.

Stellar atmospheric parameters and chemical abundances of ~ 5 million stars from S-PLUS multiband photometry

The APOGEE, GALAH, and LAMOST spectroscopic surveys have substantially contributed to our understanding of the Milky Way by providing a wide range of stellar parameters and chemical abundances. Complementing these efforts, photometric surveys that include narrowband and medium-band filters, such as Southern Photometric Local Universe Survey (S-PLUS), provide a unique opportunity to estimate the atmospheric parameters and elemental abundances for a much larger number of sources, compared to spectroscopic surveys. Our aim is to establish methodologies for extracting stellar atmospheric parameters and selected chemical abundances from S-PLUS photometric data, which cover approximately $3000$ square degrees, by applying seven narrowband and five broadband filters. We used all 66 S-PLUS colors to estimate parameters based on three different training samples from the LAMOST, APOGEE, and GALAH surveys, applying cost-sensitive neural network (NN) and random forest (RF) algorithms. We kept the stellar abundances that lacked corresponding absorption features in the S-PLUS filters to test for spurious correlations in our method. Furthermore, we evaluated the effectiveness of the NN and RF algorithms by using estimated $T_ eff $ and \( g\) values as the input features to determine other stellar parameters and abundances. The NN approach consistently outperforms the RF technique on all parameters tested. Moreover, incorporating $T_ eff $ and \( g\) leads to an improvement in the estimation accuracy by approximately $3&lt;!PCT!&gt;$. We kept only parameters with a goodness-of-fit higher than $50&lt;!PCT!&gt;$. Our methodology allowed us to obtain reliable estimates for fundamental stellar parameters ($T_ eff g\), and Fe/H ) and elemental abundance ratios such as alpha /Fe Al/Fe C/Fe Li/Fe and Mg/Fe for approximately five million stars across the Milky Way, with a goodness-of-fit above $60&lt;!PCT!&gt;$. We also obtained additional abundance ratios, including Cu/Fe O/Fe and Si/Fe . However, these ratios should be used cautiously due to their low accuracy or lack of a clear relationship with the S-PLUS filters. Validation of our estimations and methods was performed using star clusters, Transiting Exoplanet Survey Satellite (TESS) data and Javalambre Photometric Local Universe Survey (J-PLUS) photometry, further demonstrating the robustness and accuracy of our approach. By leveraging S-PLUS photometric data and advanced machine learning techniques, we have established a robust framework for extracting fundamental stellar parameters and chemical abundances from medium-band and narrowband photometric observations. This approach offers a cost-effective alternative to high-resolution spectroscopy. The estimated parameters hold significant potential for future studies, particularly when classifying objects within our Milky Way or gaining insights into its various stellar populations.